Telephone-exchange.



Patented Mar. 11,1919.

2 SHEETS-SHEE1'1.

In v e n for James L. M 0a arr/e.

' J. L. McQUAR RiE.

TELEPHONE EXCHANGE.

APPLICATION FILED NOV. 26, 1912.

J. L. McQUARRIE.

TELEPHONE EXCHANGE.

APPLICATION F ILED .NOV. 26, 1911.

, 1,296,'680.- Patnted Mar. 11,1919.

2 SHEETS-SHEET 2.

//7 van for James L MOuarr/e.

UNITED STATES PATENT OFFICE.

J'AMES L. MGQUARRIE, OF MONTCLAIR, NEW JERSEY, ASSIGNOR TO WESTERNELECTRIC COMPANY, INCORPORATED, NEW YORK, N. -Y., A CORPORATION OF NEWYORK.

TELEPHONE-EXCHANGE.

Specification of Letters Patent.

Patented Mar. 11, 1919.

npplicationnlegl November 26, 1917. Serial No. 203,971.

To all whom ,it may concern:

Be it known that I, J Arms MCQUABRIE, a citizen of the United States,residing at Montclair, in the county of Essex and State of New Jersey,have invented certain new and useful Improvements inTelephone-Exchanges, of which the following is a full, clear, concise,and exact description.

This invention relates ,to telephone exchanges wherein theinterconnection of subscribers lines is effected by automatic switchingapparatus.

More particularly it relates to the construction and operation ,ofselectively operated switches employed in exchanges of the abovecharacter.

Heretofore it has been the practice to provide for ,each switch anindividual operating mechanism comprising primary and secondary steppingmagnets, together w th other elements necessary to control the operativefunctions of the switch. In accordance with such an arrangement eachswitch of the exchange has allotted thereto its own individual actuatingmechanism, which is brought into service only at such times as theparticular switch is appropriated for use in the extension of aconnection. The actual time during which a switch operating mechanism isengaged in actuating its individual switch shaft'is of course ofcomparatively short duration. After having so performed the function ofsetting its switch shaft, the operating mechanism remains inactive untilsuch switch is again chosen to extend or complete another connection.

The main feature of the invention is to obviate the necessity of anindividual ope-rating apparatus for each switch by a switch constructionin which a group of step-bystep switches, as for example,'ten selectors,is provided with a plurality of stepping devices, any one of saiddevices being operable to engage and actuate any one 5 of the switchesof the group.

Anotlihr feature is that each of these common orinaster steppingdevices, after having completed its operation of stepping a switch intoconnection with a desired set of terminals, .does not remain inactive,but immediately proceeds to move into operative relation to the nextswitch in the group which it finds in proper condition to beappropriated for use in extending another connection. Due to thisarrangement, the total number of switch operating mechanisms for theexchange may be reduced, and the number of such mechanisms serving agroup of switches may be materially less than the number of switchescomprising the group, without reducing the percentage of availableswitches.

Still another feature is the provision of a releasing device common tothe switches of a group, and means for moving the same into position torestore any one of the switches which is in proper condition to bereturned to normal.

These and other features will become more apparent from a considerationof the following description and the appended claims.

In the drawings, Figure 1 is a perspective view showing a switchstructure arranged in accordance with one embodiment of my invention.This showing illustrates a portion of a group of selective switches, andalso the manner in which the common actu ating devices are arranged tocooperate with the switch shafts. For the sake of clearness, variousparts are shown diagrammatiand others are omitted entirely. Whileprovision is made for only two master devices it will of course beunderstood that the number of such devices depends largely upon the sizeof the group they serve and also the percentage of available switchesnecessary to afford the desired service to the particular exchangeinvolved.

Fig. 2 shows a subscribers telephone substation together with a portionof the cir cuit arrangement for controlling the operation of theswitches illustrated in the cm bodiment of Fig. .1.

Referring tofthe drawings, a plurality of step-by-step actuated switchshafts 1 arranged in a row comprise a group of switches under thecontrol of common actuating devices, Mounted on the upper end of shaft 1is a set of brushes 2, 94 and 95 adapted to be positioned in operativerelation to any desired level of terminals 3 in the vertical movement ofthe shaft, and subsequently rotated into contact with a particular setof terminals in such level. Each shaft is provided with a plurality ofvertical ratchets 4 and rotary ratchets 5 to be engaged by steppingpawls for moving the switch into its various operative positions. Eachshaft 1 also has a vertical holding ratchet 6 and a rotary holdingratchet 7.

Parallelly disposed with respect to each other and arranged adjacent totheswitch shaft 1 are a plurality of helically threaded members orendless worms 8. These worms are journaled for rotation insuitablebearings (not shown) and have secured upon their ends ratchetwheels 9. A stepping pawl 10 pivoted to the armature 11 cooperates withratchet 9 to rotate the worm a distance corresponding to one tooth foreach energization of the drive magnet 12. A supporting structure 13 isloosely mounted upon the worm 8 and is provided with any suitable meansfor engaging the endless slot diagrammatically shown at 14, whereby saidstructure and its associated elements are carried by rotation of theworm 8 back and forth before the switches of the group. A pair of fixedrods 15, upon which the structure 13 is also slidably mounted, serve asa guide and support to insure accurate movement and positioning of thestepping device. Riveted to the supporting frame 13 is a bracket 16,upon which is mounted the primary or vertical stepping magnet 17. Theupper end of support 13 is overturned and slotted to receive thearmature '18, which is pivotally attached theretofand has one endextending into position to be attracted by magnet 17. The other end ofsaid armature carries a steppingpawl 19' arranged to engage ratchet 14upon the energization of the stepping magnet when the master device isoperatively positioned before a switch shaft. The support 13 also has aninwardly extending bracket 20 to which is secured the secondary orrotary stepping magnet 21. Said rotary magnet has an armature 22, oneend of which is pivotally attached to the frame 13, and the other endprovided with a stepping pawl for engaging the ratchet 5 uponenergization of magnet 21. The

lower end of frame 13 is bent over to fornr a supporting table 23, uponwhich'is mounted a magnet 24. This magnet has an armature 25 alsopivoted to frame 13. Armature 25 has its free end projecting into suchposition that upon the energization of magnet 24, when the master deviceis positioned before a switch shaft 1, said armature engages a pin 26upon a rod 27 for the purpose ,of urging such rod in a downwarddirection. The function of this rod will hereinafter be more fu lyconsidered. It will also later appear t at magnet 24 serves to resetcertain auxiliary switches associated with the operating circuits of theselective switch.

Positioned before and individual to each switch shaft l is a set ofcontact springs 28. This set comprises seven pairs of contacts, theupper six of which are-open and the lower one closed while there is notension exerted upon the spring members. When,

i,296,6so

however, a master mechanism positions itself before the switch, a pin 29presses against the under side of the block 30 to close the firstmentioned group of contacts and to open the lower set. At the same timea pin 31 of insulating material, carried on the underside of the table23, bears on the contact spring 79 and forces it to close on itscooperating spring. A strip 34 having an integral contact member 35 isso arranged between switch positions as to normally remain in openrelation to a cooperating contact spring 36. But when a master device,under the influence of the driving worm 8, leaves its position ofoperation before one switch, the pin 31 presses strip 34 downward andretains the same in closed contact with spring 36 until said device hascompleted its travel to its operative position before the next switchshaft 1, at which time the strip 34 is released and the contacts 35, 36are again opened.

Each stepping mechanism has a set of contact strips generally designatedat 37, arranged parallel to the path of movement of said mechanism, andextending before all the switches of the group. Said set comprises nineseparate contact strips, which, as shown in Fig. 1, are insulated fromeach other by the interposition of insulating material, and may besecurely held in proper position by any convenient means. Securelymounted upon the supporting table 23 of-the frame 13 is a set of brushes38, one for each of the strips of the set 37,

coiiperatingwith said strips in such manner as to maintain a slidingresilient contact therewith throughout the complete travel of the masterdevice. The brushes of the set 38 are insulated from each other, and, aswill more clearly appear hereinafter, serve to convey current to andfrom the operating magnets carried by the movable structure.

Mounted upon a pivot 39 are the vertical and rotary holding dogs 40 and41 respectively, which coact with the holding ratchets 6 and 7 to retainthe shaft 1 in its actuated position. An endless worm 42, similar toworm 8, is arranged adjacent the switch shaft 1, a'nd'has mountedthereupon the release magnet supporting frame 43. Said frame engages theendless spiral slot 44 so as to be driven axially along the worm 42 whenthe same is rotated. The ratchet 45, actuated by armature 46 of thestepping magnet 47, serves as a driving means for the worm. A rod 48,upon which the frame is also slidably mounted, serves to guide the samein its movement before the switch shafts. The release magnet 49, whichissecured to themovable frame 43, is arranged'so that when positionedbefore a switch shaft and energized it will attract the flanged portion50 of dog 41 to withdraw both holding dogs from their engagement withratchets 6 and 7, thereby permitting the shaft 1 torestore. Current isconveyed to magnet 49 by way of the feed strips 51, 52 and brushes 53,54. An insulating finger 55, carried on the arm 56 of the frame 43,cooperates with the contact members 57 and 58 in a manner similar tothat described in connection with the master operating mechanisms. v

Having described in detail one embodiment of a switch structure in whichmy present invention resides, I will now explain the manner in which itis calculated to operate by describing the circuits designed to performthe various functions involved in the extension of a telephoneconnection. For the purpose of explanation it will be assumed that thetelephone system in which the present invention is used, employs finderor other preliminary switches, first selectors, second selectors, andconnectors. The switches shown and described in the drawings will beconsidered as used in the capacity of second selectors. According to thewell known practice of trunking, each level of trunks in a firstselector leads to a group of, say, then second selectors, all of whichhave access through the succeeding connectors to any line in a given onethousand lines. Therefore, since the second selector switches may beconsidered as divided into groups according to the numerical grouping ofsubscribers lines, a convenient adaptation of the present invention isto provide each such group of second selectors, as shown in thedrawings, with a plurality of common stepping devices. A first selector,in testing any particular level of its trunks, may then obtain anysecond selector of a group that is served by a number of commonactuating devices.

Assume that the subscriber at substation 59, Fig. 2, desiring toconverse with some other subscriber, removes his receiver from the hookto start the operation of a finder or line switch. Such switch, which isdiagrammatically illustrated by the broken lines in the figure, operatesin the well known manner to connect the line conductors 60 and 61 to thetrunk conductors 62 and 63, terminating in brushes 64 and 65 of a firstselector switch. The subscriber now operates his sender to transmit agiven number of impulses to the operating mechanism of the firstselector, whereby the brushes 64, 65, 66 are moved into operativerelation to the desired level of trunk terminals. Terminals 67, 68, 69represent the first set of terminals in such level and are associated bymeans of trunk conductors 70, 71, 72 with brushes 94, 95, and 2 of asecond selector switch, as those shown in Fig. 1. Assume now that theswitch shaft 1 associated with the trunk 7 0, 71, 72 is in its normalrestored position, and that a master stepping mechanism, such as the oneshown in Fig. 2, has previously been positioned before such switch inreadiness to operate the same as soon as taken for use This being thecase, the pins 29 and 31 on the supporting frame 13 are holding the contacts of the set 28 and contact 32 respectively in their alternatepositions, whereby contacts 7 3 to 79 inclusive, Fig. 2, are closed,while contact 80 is open. The contact 80 by being open places a breakpoint in the following circuit from the test contact 81" to ground: testcontact 81, conductor 82, contact 80, conductor 88, contact 80,conductor 84, to ground at the off-normal contact 85.

Therefore, when the first selector switch begins its secondary orhunting movement and takes its first step onto the trunk terminals 67,68, 69, no guarding ground potential willbe found by test brush 66 upontest terminal 69, thereby indicating that the switch associated with thetrunk 70, 71,72 1s in proper condition to be selected. Thereupon thefirst selector comes to rest and-extends'the connection by way oftrunkconductors 7 0 and 71 to the switch shown in th drawing. A circuit isnow closed for the line relay 86 from free pole of battery, upperwlnding of such relay, upper armature and contact of cut-off relay 87,conductor 88, closed contact 78, conductors 89 and 7 0, terminal 67,brush 64, conductors 62 and 60, over the loop of substation 59,c0nduct0rs'61 and 63, brush 65, terminal 68, conductors 71 and 9(),closed contact 74, conductor 91, inner lower armature of cut-ofi relay87 lower winding of relay 86, to ground. Relay 86 on attracting itsarmaturecloses a circuit for the slow relay 92, traceable from ground,armature and front contact of relay 86, relay 92, to the free pole ofbattery. The relay 92 energizes and at its right-hand armature places aground, by way of the following circuit, upon all multiples of the testconductor 72 at the first selector switches, so

that any other switch testing such multiples will find the same guardedso long as relay 92 remains energized: ground, right-hand armature andcontact of relay 92, conductor 93, closed contact 77, conductors 82 and72, to test contact 69 and other multiples thereof.

The calling subscriber, proceeding to manipulate his sender inaccordance with the second digit of the called number, interrupts theabove traced circuit of line relay 86, thereby causing the same tovibrate its ar mature a corresponding number of times. Upon the firstretraction of said armature the following circuit is closed for the slowrelay 96: ground, armature and back contact of relay 86, inner left-handarmature and front contact of relay 92, winding of relay 96, to batteryand ground. Relay 96 by energizing establishes acircuit for escapemagnet 97 from ground, armature and contact of relay 96, side-switch arm98-and its first position contact, winding of magnet 97, to battery andground. The following circuit is also closed at the same time for theprimary stepping magnet 17 of the master mechanism: ground, armature andback contact of relay 86, inner left-hand armature and front contact ofrelay 92, side-switch arm 99 and its first position contact, contactstrip 100, brush 101, winding of stepping magnet 17, brush 102, contactstrip 103, to battery and ground. Said magnet 17 thereupon attracts itsarmature 18 and through the agency of pawl 19 and the vertical ratchet 4steps the shaft 1 up one step. Likewise, for each succeeding retractionof the line relay 86, an impulse is sent to magnet 17 and the shaft 1 iselevated to position its brushes 94, 95 and 2 in operative relation tothe desired level of contacts in the bank 3.

At the termination of the second series of impulses the line relay 86holds its armature attracted, and after a sufficient period has elapsedrelay 96 denergizes, thereby opening the circuit of the escape magnet97. Magnet 97 by deenergizing allows the side switch to escape intosecond position. In such position magnet 97 is immediately energizedover the following circuit: free pole of battery, winding of magnet 97,sideswitch arm 98 and its second position con tact, conductors 104 and105, closed contact 78, conductor 106, secondary off-normal contact 107,to ground. lVith the side switch in second position a circuit is alsocompleted as follows for the secondary magnet 21 of the mastermechanism: ground, side-switch arm 108, contact strip 109, brush 110,contact and armature of magnet 21, brush 111, contact strip 112, tobattery and ground. Upon energizing, the stepping magnet 21 attracts itsarmature 22 to automatically rotate the shaft 1, carrying the brushes94, 95 and 2 step by step, over the trunk terminals of the selectedlevel. Busy trunks are identified by the presence of a ground upon theirtest terminals. At the first rotary step of the shaft 1 the secondaryoff-normal contact 107 is opened, thereby opening the energizing circuitpreviously traced for the escape magnet 97. If, however, the first trunkin the level upon which the brushes 94, 95 and 2 are momentarilyresting, is busy, a holding circuit is established for escape magnet 97as follows: battery, winding of magnet 97, side-switch arm 98 and itssecond posi tion contact, conductor 104, closed contact 75, conductor113, test brush 2, to the grounded test terminal 114. The side switchthus remains in position 2 and the magnet 21, interrupting its owncircuit, continues to rotate the switch until its brushes encounter anidle trunk. When this occurs the escape magnet becoming deenergizedsteps the side switch into position 3, thereby bringing the selectorswitch to rest.

As the side switch arrives in third position a circuit is completed fromground, side-switch arm 108, contact strip 115, brush 116, winding ofmagnet 24, brush 117, contact strip 118, to battery. Magnet 24, uponattracting its armature 25, Fig. 1, causes the same to engage the pin 26on vertical rod 27 to move said rod downwardly against the end of lever119. Lever 119 being tilted about its pivot 120 presses against the pin121 to engage the springs 81, 122 and 123 with their respectivecontacts. As seen in Fig. 2, this results in extending the trunk 70, 71,72 through to brushes 94, 95 and 2 of the selector, as soon as saidselector has completed its secondary movement. The shouldered end oflever 119, against which the upper end of the intermediate lever 124normally rests, as shown in the figure, being tilted upwardly by theaction of rod 27, permits lever 124 to escape its engagement with theshouldered end of lever 119 and to rotate, by the tension of spring 125,so that its upper end now bears against the under straight surface ofsaid. lever 119. This new position of lever 124 locks lever 119 in theposition to which it was actuated by magnet 24 to hold contacts 122,123, 81 closed during the engaged period of the switch, since, as willpresently appear, the magnet 24 soon becomes inactive after havingactuated the rod27. The above described rotation of intermediate lever124 is made possible at this time due to the fact that the ratchet 7having moved up out of contact with lever 126, the retractile spring 127withdraws lever 126 out of the path of said lever 124. The magnet 24also acts upon its energization to reset the side switch to its normalposition. l/Vhile the side switch is momentarily standing in position 3before being reset by magnet 24, the following circuit is established:ground, sideswitch arm 108, contact strip 115, brush 116, left-handarmature and contact of relay 24, brush 128, contact strip 129,conductor 130, thence by one path to the contact and armature of themaster drive magnet 12, winding of said magnet to battery; and byanother path to the winding of cut-off relay 87, to battery. Relay 87and magnet 12 energize in the circuit traced. Reset magnet 24, which wasmomentarily energized while the side switch stood in position 3, doesnot, however, immediately deenergize when said switch restores, butlooks up as long as slow relay 92 retains its armatures attracted overthe following circuit: battery, contact strip 118, brush 117, winding ofmagnet 24, righthand armature and contact of said magnet, brush 131,contact strip 132, conductor 133, outer left-hand armature and frontcontact of relay 92 to ground. Magnet 24 by holding its armaturesattracted affords a new energizing circuit for relay 87 and magnet 12*during the time that slow relay 92 is holding its armaturesin theirattracted position'.v This circuit is traceable from ground, outerleftdiand armature and front contact of relay 92, conductor 133, contactstrip 132, brush 131, contact and right-hand armature of magnet 24,-left-hand armature and contact of said magnet, brush 128, contact strip129, conductor 130, to magnet 12 and relay 87 as above tracedn Relay 87by -energizing cuts off the line relay 86, and-the master'drive magnet12 byv energizing in the above traced circuit vibrates its armature 11to engage ratchet 9, and thereby rotate the endless worm 8. Rotationofsaid wormcauses the supporting frame '13 with the master steppingmagnet to move away from its operative position before the switch justactuated and to advance toward the next switch in the group. At thefirst movement of said master device, the pins 29 and 31 permit thecontacts 73 to SO-inclusive to assume their normal positions as shown inFig. 2. Furthermore, the pin-31, having moved onto the strip 34, pressesthe same into contact with spring 36. This results in the closure of thefollowing circuit which takes the place of the circuit previously tracedfrom the magnet 12 and relay 87 in parallel therewith to ground atslowrelay 92: ground, contact strip 34, contact 36, conductor 134i, outerleft hand armature and back contact of relay 92, conductor 130, tomagnet 12 and also relay 87. Thiscircui-t keeps the magnet 1-2-actuatingand insures a complete movement of the master device-to its operativeposition before the next switch. If, upon the master device reaching itsposition before the next switch, such as the switch representedgenerally by the contact group 28 in Fig. 2, andthis switch is alreadyactuated, the following circuit is established: from magnet 12 and relay87 in parallel, conductor 130, outer left-hand armature and back contactof relay 92, conductor 134C, to a'closed contact corresponding to 79 ofthe set 28", a conductor similar to 135, to ground at anofi' normalcontact 85 of the busy switch. Therefore the drive magnet 12 con--tinues to move the master device past the actuated switch and on to thenext one in order; 4

' Assume-now that this nextswitch is in its normal position and has amaster mechanism standing before it, similar to the one illustrated'indetail in Fig. 2, andwhich in its travel before the switches cooperateswith the lower sets of contacts in the figure, such as the set-73" to80' inclusive. In such event the master'device under discussion uponarriving before such switch completes the following circuit for itsrelay 87 and drive magnet-12: relay 87 and magnet 12 in parallel, frontcontact and lower armature of relay 87, conductor 136, a closed contactsimilar to76 of the set before the assumed switch, a conductor similarto 137, a closed contact similar to 7 6 before which there is already amaster device resting, over the conduct-or 136, to ground at the lowerarmature and back contact of the cut-off relay similar to 87 of suchmaster device. Hence the magnet continues to energize and the masterdevice passes by said switch, which already has a master device restingbefore it, and in the manner already described goes on to the nextselector switch.

If the next switch encountered is in nor mal position and has no masterdevice already before it, then when the seeking master device assumesits position before such switch, the operating circuits above describedfor the drive magnet 12 and relay 87 are opened, and said device comesto rest, ready to operate said switch when taken for use.

Returning to the point where the first selector had positioned itsbrushes 64:, 65 and 66 upon the terminals of trunk 70, 71, 72, it willbe remembered the assumption was that the second selector switchassociated with said trunk was idle and had a master device positionedbefore it. If, however, the switch is idle but has no master deviceassociated therewith, it is obvious that said switch is not in propercondition to be selected and should therefore test busy to the precedingswitch. This condition is obtained as follows: Since there is no masterdevice before the switch, all of the contacts 80,80, etc, are closed sothat when brush 66 makes its test of trunk 72 a ground is found thereon.The circuit affording this ground is traceable from test trunk 7 2,conductor 32, through the closed contacts 80, 80, etc, in series, toground at the off-normal contact 85.

If the switch hadbeen previously actuated and was busy extending a callwhen the above mentioned test was made, a ground would have been presenton test conductor 72 by way of test terminal 114, brush 2, and contact81. From the foregoing it is apparent that a switch, in order to beselectable to a preceding switch, must not only be idle and restored butmust also have amaster stepping mechanism associated therewith. It isalso obvious that a master device having per formed its function on oneswitch, immedi ately starts out in search of the next switch in orderthat is incondition to have a master device associated therewith.

Should, for any reason, the subscriber abandon his call while the sideswitch is in second position, the following circuit is closed for thereset magnet 24 to restore the side switch to normal: ground, armatureand back contact of relay 86, inner left-hand armature and back contactof relay 92, conductor. 138, side-switch arm 139 and its sec- 0ndposition contact, contact strip 140, brush 141, winding of magnet 24,brush 117, contact strip 118, to battery and ground. At the same timethe following circuit is established for the drive magnet 12 to move themaster device away from the selector switch: ground at the armature ofrelay 86, orer the circuit just traced to the brush 141, thence by wayof the left-hand armature and contact of magnet 24, brush 128, strip129, con ductor 130, magnet 12 to battery.

Considering now the release mechanism it will be described how themagnet 49 which is common to all switches of a group is capable oflocating such switches as are in proper condition to be returned totheir normal position. The magnet 47 which drives the worm 42, receivesits energization over the following circuit: free pole of battery, winding of magnet 47, armature and contact of said magnet, contact andarmature of relay 142, to ground. So long as relay 142 remains inert,the magnet 47 interrupting its own circuit will drive the release magnet49 back and forth before the switch shafts 1. Relay 142 is arranged toreceive sufiicient current through resistance 143 only when conductor144 is free from ground connections. If magnet 49 passes before a switchthat is idle the pin 55 on arm 56 by closing contact 58 places a groundon conductor 144 as follows: ground, off-normal contact 85, conductors84 and 113, closed contact 58 to conductor 144. The relay 142 remainsdeenergized and magnet 49 continues its movement, due to a ground onconductor 144 by reason of the closed contact 57, to the next switchposition. If the next switch is being actuated a ground is extended toconductor 144 from a secondary off-normal contact 107, a conductorsimilar to 106, a closed contact similar to 78, a conductor as 104, aclosed contact similar to 75, a conductor similar to 113, aclosedcontact 58, to conductor 144, while said switch is in its primarymovement. But if the switch is in its secondary movement, contact 107 isopen, and the ground is now afforded from busy test terminals 114, byway of a conductor similar to 113 to conductor 144.

VVhe-n, however, the release magnet 49 positions itself before a switchwhich is idle and in condition to be restored, no short-circuitingground is present on conductor 144, and consequently relay 142 attractsits armatures. This opens the circuit of magnet 47 thus stopping magnet49 in operative relation to the flange 50. A circuit is also closed formagnet 49 from ground, armature and contact of relay 142, strip 51,brush 53, winding of magnet 49, brush 54, strip 52 to battery. Magnet49, thereupon attracts the flange 50 to rotate the holding dogs 40 and41 out of engagement with the holding ratchets 6 and 7.. This movementof flange 50' carries the trigger 145 behind the catch 146 of lever 124,thereby locking the holding dogs 40 and 41 away from their ratchets toinsure a complete restoration of the shaft 1. At the same time finger147 closes contact 148, whereupon a ground is again placed on conductor144, which in turn deenergizes relay 142, and the drive magnet operatesto drive the release mechanism to the next switch. When shaft 1 reachesnormal, the ratchet 7, through the agency of lever 126, restores levers124 and 119 to their normal positions as shown in Fig. 1, therebyopening contacts 122, 123, 81. and 148, and also unlocking holding pawls40 and 41.

In detailing the successive steps and op erations, and accounting forthe various conditions to be met with in building up a connection in atelephone system embodying my present invention, I have described myimproved switches as serving in the capacity of second selectors.However, it will be clearly understood that the above description doesnot limit the scope of the invention, but is merely exemplary of thenumerous adaptations contemplated thereby. It is obvious that theswitches shown and described herein may be used as any one of theparticular classes of switches employed in extending a telephone orother connection between two points.

No claim is made herein to the features of the circuit arrangementdisclosed, the same being described merely for the purpose of enabling amore thorough understanding of the manner in which the switches operate.

What is claimed is:

1. In a telephone exchange, a group of switches, a stepping devicecommon to said switches, means for moving said device into position toengage and operate one of said switches, and a release device common tosaid switches for restoring the same to their normal positions.

2. In a telephone exchange, a group of switches, a common steppingdevice movable in a path forth and back before the switches of saidgroup, and means for driving said device into position to engage andactuate any one of said switches.

3. In a telephone exchange, a group of switches, a stepping magnetcommon to said switches and arranged to actuate any one thereof, andmeans for moving said magnet into operative relation to one of saidswitches.

4. In a telephone exchange, a group of switches, a stepping magnetcommon to said switches and arranged to actuate any one thereof, and asecond stepping magnet for moving said first magnet into operativerelation to each of said switches.

5. In a telephone exchange, a group of switches, a plurality of steppingmagnets common to said switches and arranged to actuate any one thereofin a plurality of directions, and means for moving said magnets intooperative relation to each of said switches.

6. In a telephone exchange, a group of switch shafts, a worm adjacent tosaid shafts, a common stepping mechanism for actuating said switchshafts, said mechanism being mounted upon said worm and having anoperative position thereon for each switch shaft, and means for drivingsaid worm to move said mechanism from one position to another.

7. In a telephone exchange, a group of switches, a commonl operatingdevice movable in a path forth and back before the switches of saidgroup, and means for driving said device to move the same into positionto engage and operate any one of said switches in a plurality ofdirections.

8. In a telephone exchange, a group of step-by-step switch shafts, anelectromagnetically operated stepping pawl arranged to engage andactuate any one thereof, and means for moving said pawl into operativerelation to any one of said shafts.

9. In a telephone exchange, a group of switches, a unitary structuremovable in a path before the switches of said group, said structureincluding primary and secondary stepping magnets common to and adaptedto actuate any one of said switches, and means for moving said structureto position the same in operative association to one of said switches.

10. In a telephone exchange, a group of switches, a plurality ofdevices, each arranged to engage and movesaid switches in a plurality ofdirections, and means for op eratively associating any one of saiddevices with any one of said switches.

11. In a telephone exchange, a switch shaft, a plurality of steppingdevices, each arranged to engage and actuate said shaft in a pluralityof directions, and means for operatively associating any one of saiddevices with said shaft.

12. In a telephone exchange, a group of switches, a plurality of commondevices arranged to engage and operate said switches,

a-screw shaft individual to each device for moving the same intooperative association with any one of said switches, and means fordriving said shaft.

13. In a telephone exchange, a group of switches, a plurality of unitarystructures common to said switches, each including pri. mary andsecondary operating magnets, and means for moving any one of saidstructures into position to operate any one of said switches.

14. In a telephone exchange, a group of stepby-ste switches, a pluralityof stepping magnets common to said switches, and stepping means forplacing any one of said magnets in position to move any one of saidswitches.

15. In a telephone exchange, a group of switches, means for actuatingsaid switches, a releasing mechanism common to said switches, andstep-bystep means for moving said mechanism into position to restore anyone of said switches to its normal position.

16. In a telephone exchange, a group of switch shafts, means for movingsaid shafts to their operative positions, a worm arranged adjacent saidshafts, a release magnet common to said shafts mounted on said worm andhaving positions thereon for releasing each of said shafts, and astepping magnet for driving said worm to move said release magnet to anyof such positions.

17 In a telephone exchange, a row of vertical switch shafts, a pluralityof rotatable screw shafts arranged adjacent to and ex tending before allthe switches in said row, a supporting structure mounted upon each screwshaft and arranged to be moved longitudinally by rotation of said screwshaft, a pair of stepping magnets mounted upon each structure foractuatin said switch. shafts in two directions, each pair of magnetshaving an operative position before each switch in said row, andstepping means for rotating each of said screw shafts.

In witness whereof, I hereunto subscribe my name this 22nd day ofNovember A. D., 1917.

JAMES L. MCQUARRIE.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, I). G.

